This invention refers to a device, in particular for washing-machines, the purpose of which is to open the machine door from a distance by means of the push-button positioned on the control panel, the said device also houses the instantaneous locking device and delayed door release device, usually known as door lock.
Both electromagnetic and mechanical devices of this kind 'already exist and are well known, the latter designs usually operate on the swinging type closure hook causing the engaging tooth of the hook itself to retract.
Moreover, electro-mechanical devices are considerably more expensive, due to the fact that as has been mentioned mechanical devices operate by displacing the closure hook,require a considerable excursion of the push-button during the opening phase, hence a high degree of precision is required in the working dimensional tolerances of the cable, and requiring considerable force to be exerted on the push-button.
An electro-mechanical device is disclosed, for instance, by EP-A-0 600 390.
The device subject of the invention is based on a mechanical design and its fundamental advantage is that of releasing the machine door hook and therefore the subsequent opening of the machine door by exerting a limited force on the control push-button and requiring a short excursion of the push-button as in electro-mechanical devices.
An additional advantage of the invention is that it can also operate with a fixed machine door hook design, though its application and correct operation continue to be possible on swinging machine door hook designs.
A further advantage is that of allowing the conversion from a mechanical device to an electro-mechanical device by replacing the wire actuated device that operates the release mechanism with an electromagnet. However, the said electromagnet has a much smaller size compared with the size required for known electro-mechanical devices and this is made possible since only a small force is required resulting from the device features that shall be described below.
The invention is characterised by the fact that whereas for known mechanical devices all the work to release the machine door closure hook is performed by the force exerted on the release push-button and therefore a significant force is required to adjust the hook and an extended excursion of the push-button is necessary, for the device subject of the invention the hook is engaged by means of a swinging blade positioned under the hook and the force required to release the machine door closure is exerted by a spring that is pre-compressed by the hook itself during the door closure phase and consequently the force exerted on the machine door opening push-button is limited to the force required to overcome the friction between two small surfaces in contact, therefore the movement of one of the two surfaces causes the previously pre-compressed spring to expand as specified in claim 1.
The invention will be more clearly understood through the description of an example of fulfilments provided solely for the purposes of illustration and is not exhaustive, as detailed by the three attached drawings which represent:
With reference to figures 1 to 9 both (1) the device according to the invention and (2) the door hook of a washing-machine.
The device consists of a body (3) which houses various parts making up the device itself.
(4) indicates the machine door locking latch the function of which, once the washing-machine door has been closed and the operating command has been activated, is to instantly operate the door locking mechanism and at the end of the washing cycle to impart the delayed action to the door release mechanism.
The machine door locking device is not shown in the drawings, but is part of a separate body housed inside body (3) of the device as foreseen in the invention, behind the components that impart the locking and release action to the machine door hook. The various device components are housed inside body (3):
These are the main components of the device which serve to operate the remote locking and release mechanisms of the machine door hook, but the said device includes other components which have a safety function, to prevent machine operation with the door open, or when the door is not closed securely.
A first safety device consists of a third extension (14) positioned in relation to the cursor rear section (5) which, when the machine door is in the open position, lies under latch (4) of the door locking device preventing it from completing the closure phase should the machine be operated with the door in the open position.
Another safety device consists of a fourth extension (15) that forms a rear extension of the second blade holder slide (8) which in the event the hook is not securely closed, positions itself under the machine door locking latch (4) preventing it from completing the closure phase and consequently inhibiting operation of the machine, (refer to fig. 8 which represents one of the hook positions during the opening phase, but can correspond to a hook position when the door is in a partially closed condition).
The mechanism operates as follows.
With the door in the open position (refer to fig.1, 2 and 3) cursor (5) is in the fully forward position; the first spring (6) is extended and the fourth spring (12) and third spring (13) are also extended.
The third extension (14) of cursor (5) is positioned under the machine door locking latch (4), acting as a safety mechanism. The second blade holder slide (8) is also in the fully forward position with the corresponding second spring (10) also extended, (refer to fig. 2).
The third slide (11) is fully inserted inside its seat with its surface (18) resting against surface (17) of the first slide (7).
When hook (2) is introduced, refer to fig. 4, 5 and 6 the said hook enters with his head and causes the hook locking blade (9) and the front section of cursor (5) to move backwards therefore compressing the first spring (6) and the second spring (10). Once the hook head moves beyond blade (9) the second spring (10) expands carrying blade (9) under the hook edge, while the hook head maintains its pressure against the forward section of cursor (5), maintaining the first spring (6) compressed against the first slide (7) and maintaining the third spring (13) also compressed. By this arrangement of the various device components, according to the invention, when the machine is operated, the door closing latch (4) can move into its seat (20) in the third slide (11) thereby securing the third release slide (11) (refer to fig. 4, 5 and 6) and preventing the door from opening during the complete washing cycle.
It must be noted that with the various components of the device arranged as described above, the first extension (7') of the first slide (7), which as mentioned previously is introduced inside the body of the second blade carrier slide (8), and the corresponding rear wall of the second blade holder slide (8), against which the said first extension (7') pushes during the release phase, are not in contact with one other but an empty gap of a few tenths of a millimetre exists between the two parts.
The machine door locking latch (4) returns to its retracted position with the appropriate delay leaving seat (20) vacant on completion of the washing operation, refer to figures 7, 8 and 9.
Pressing the operating push-button located on the machine control panel by means of wire (16) in this condition displaces the third release slide (11), which requires very little force, since only the friction between the parts in contact (17) of the first slide (7) and (18) of the third slide (11) needs to be overcome. The first spring (6) is subsequently able to extend itself at the rear and to pull the first slide (7) backwards, while the first slide (7) will pull, by its first extension (7'), the second blade holder slide (8) and the blade (9), enabling the machine door hook (2) to disengage (refer to fig. 8).
The small gap between the first extension (7') of the first slide (7) and the corresponding surface of the second blade carrier slide (8) ensures the latter is firstly pushed by the first extension (7'), this serves the purpose of overcoming the initial separation friction between the hook locking blade (9) and the edge of the hook (2) which rests on blade (9).
Once hook (2) has moved out of its seat, the expansion of the cursor resetting spring (13) returns cursor (5), second blade holder slide (8) and first slide (7) to their initial position; in addition, the expansion of the fourth spring (12) returns the third slide (11) to its initial position, as shown in fig.1, 2 and 3.
The third slide (11) may be connected to the door opening push-button on the control panel also by a small and low-energy electromagnet.